Process and apparatus for distillation of bituminous material



H. KOPPERS July 22, 1930.

' PROCESS AND APPARATUS FOR DISTILLATION OF BITUMINOUS MATERIAL Filed July Vi, 1921 &

Patented July 22, 1930 I uNrrEo STATES- PATE T OFFICE HEINRICH KOPPERS, OF ESSEN-RUHR, GERMANY, ASSIGNOR TO THE KOPPERS DE- VELOPMENT CORPORATION, OF PENNSYLVANIA PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PROCESS AND APPARATUS FOR DISTILLATION OP BITUMINOUS MATERIAL Application filed July 7, 1921, SerialNo. 483,053, and in Germany November 5, 1919.

The invention relates to a .process and arrangementfor the distillation of bituminous material for the purpose of obtaining originqil tar, i. e., tar that has not as yet been rec: ti ed or subjected to distillation, having for its principal objects to avoid overheating of said substances and a secondary decomposition of the, oils .and to conserve heat, by avoiding direct firing and by tempering the heating gas by an admixture of air.

In the distillation of bituminous substances for obtaining primary, or original tar, that is tar that has not been subjected to distillation or rectification as yet for the removal of other elements, it is a fundamental prerequisite to avoid overheatings, even of only a local character, and thus secondary decom-' position of the resultant oils. In the direct firing of such retorts it is notpossible in actual practice to obtain-a careful regulation of the heat, especially such regulation as is required for the distilling chambers of fireproof material when they are disposed as is usual. Tothis must be added that chamotte andsi'milar fireproof stones possessso poor a heat-conductivity coefficient that the efficiency of the distillin device becomes low.

The invention entire y dispenses with the direct. firing of the distilling chambers for such distillation and effects such heating by means of a gaseous heat earrierwhich has been previously char ed with the requisite quantity of heat.-

amount of heat produced by the burning pf a gas or some other fuel outside of the distilling device properand possessed of a high temperature is 'tempered'by the" admixture Y of surplus air, to such an extent that with due-consideration of the requisite drop in temperature, the temperature necessary for the heating of the distilling chambers is afforded. As a result of this equalization or tempering purely local overheating can also be avoided, and also the lowering of the temperature renders the use of iron heating-j ackets for the distilling chambers possible as a 1 general rule. By this means, not onlyis the efliciency of the heat-transmissionto the material to be heated increased considerably or that purpose therier yields its heat surplus over and above the average distilling temperature, to the distilling chambers and leaves the distillingchambers still at a relatively high-temperature. The heat losses which would otherwise result are avoided, and the heat surplus rendered serviceable for the process, by conducting the waste heat in each case througha heat recovery plant to impart heat thereto and in which the'air required at a later time for the burning and diluting of the healing gases is preheated ac cordi'ngly. In this manner, there practically results'a cycle as regards the heat, during which the heat quantity left after the average distilling temperature has been abstracted, is, as it were, continuously kept in the process and neednot be produced anew upon each reversal and only the heat actually consumed in carrying out the distilling process (with some waste as described below) needs to be produced anew.

As the waste heat naturally leaves the heat recovery plant with a certain heat surplus still remaining in it, it might appear advisable to utilize the gases thus remaining from the heat recovery plant over again for dilution; this, however, is not practicable for the following reasons: In the first place, it is always necessary to use fresh air anyway for bringing about the combustion, while, on the other hand, a greater or lesser part of the waste heat would also have to be withdrawn from the process as newly produced surplus. The above mentioned use of the waste heat over again therefore could not be carried out -without a loss anyway. .On the other hand,

. derstood there is shown in the accompanying drawing means for carrying the same into practical effect, without limiting the invention to the particular construction which is shown for the purposes of illustration and explanation. In said drawing Fig. l is an elevation, partly in section, of a distillation plant embodying a form of the physical part of the inventlon and adapted for carrying out said process.

Fig. 2 is a horizontal section, on a larger scale, of one of the distillation chambers.

Fig. 3 is a fragmentary enlarged View of the top of the left hand retort shown 1n Fig. 1,

A series of distilling devices a are connected by pipe connections b and c to the conduits d and e which lead to the regenerators f and 9 built after the fashion of the stone blast heaters. Each of the regenerators f and g are connected with the chimney by connections 9', 1" which can be closed to the chimney at u, and are connected with the outside air by connections 8, s which can be closed to the outside air at t. The central shafts h and i, of the respective regenerators f and g, 'are connected with the conduits d and 6, respectively, and are provided with means for producing gas flames 7c and Z, whlch gas flames burn constantly in the respective shafts h and 2'. In one of the operating stages the outside air acting as the gaseous'heat-carrierenters through the air pipe 8 and flows through and is preheated by the heat stored up n the'fireroof checker work of the regenerator f which has been highly heated by absorption of heat from the waste heat of the preceding operating stage, and in passing through the regenerator f the atmospheric a1r is pre heated prior to its passing through theshaft k to the gas feed k, where a further rise 1n the temperature of the atmospheric a r takes place while a part of the atmospheric arr 1s burnt. At this temperature, which is assumed at about 550 C., the gas enters, through conduit d and connection I), the heating shaft on of the distilling devices or retort structures a, which retort structures consist of masonry walls in which a stationary iron cylinder n that forms the retort is arranged in spaced relation. Insideof but spaced from the iron cylinder n there is provided a slowly rotatable sleeve 0 made after the fashion of the brown coal distilling retorts, which sleeve 0 consists of rings overlapping eachother in a Venetian-blind manner. These sleeves 0 are supported for rotation at their upper ends 0 by a vertical axial drive shaft 0 which may be driven from below in the usual and well known manner, for instance, as shown in the Norwegian Patent No. 18935. The annular space of shaft m between it and the masonry wall is divided by a vertically extendingpartition p in shaft m, so that the gases entering through I), after washing around the jacket, will leave the shaft m of the distilling device a through the pipe 0. glhe fresh material g to be distilled is intro- 'duced into the retorting space within the cylinder n at any time at the top into the annular space between it and 0 and gradually passes downwardly; in this manner, due to the uniform heating, the primary or originaltar is expelled and, by reason of the immediate pas sage of the gases into the inner space of the member 0, a subsequent decomposition is also to direct the bituminous material to the space,

between the sleeve 0 and wall 71.. The gaseous heat-carrier leaving the distilling devices through the connections 0 passes into the conduit e to enter the shaft Z of the heat storer 9, whose air connection 8 is closed during such flow of gases, and from the heat storer g the gases flow out through the shaft 1" which is connected with the chimney; in this connection the waste heat gases are highly preheated accordingly by the burner Z prior to flowing through the checkerbrick in the regenerator chamber 9 to yield sufiiciently intense surplus heat to the checkerwork of the regenerator 9 so asto store up sufficiently intense heat in the checkerwork for heating up air upon reversal. From the regenerator g the cooled waste gaseous-carrier passes to a chimney throughthe connection 1" and enters the chimney relatively cool. This operation can be reversed by proper adjustment of the air and flue valves t and u, to cause the entrance of air at s and its exit at 1'.

For the feeding of the surplus air at any time, to temper. it so as to have the proper temperature after being'flame heated, the main prerequisite is that the surplus air is fed to the air current forming the heat-carrier before the heat-carrier reaches the distilling devices. Locating the permanent gas supply in the path of the carrier as described has the advantage that a special reversing of the gas current contrary to the air and chimney connections is rendered entirely superfluous. In this connection the heat of the gas flame burning constantly in the regenerators is first imparted to and transmitted by the waste heat-carrier (air) from the devices a to the fire proof checker work in order to be stored therein tobe later absorbed by and conducted back into the process by the fresh air at the time of the draft reversal, which draft reversal takes places about every half hour. Aside from the small losses, in this manner of operation, the amount of gas required by continuous burning of the gas flames 7c and Z will not be more than an amount which would be required and that would correspond to a doubly large gassupply which would be required were the burners lc'and'l used only during the time in which their respective regenerators were serving as an air preheater. It is also easier to regulate the gas supply to the burners k and I automatically according to the distilling temperature to be attained when they are both used continuously instead of intermittently. I Y i What is claimed is 1. Apparatus for low temperature distillation of bituminous material for the production of tar, in combination: two regenerators operable in alternation for preheating air and for storing of heat; a plurality of distilling devices each comprising a fireproof shaft, an iron jacket therein and spaced from said shaft to provide an annular flue space through which a heating medium flows, a vertically extending partition within said annular flue space for controlling the flow of the heating medium therein, a sleeve within said jacket and spaced therefrom to form a retorting space for passage of bituminous material downwardly therethrough, said sleeve having passages for flow of distilled gases or vapor from said retorting space.

directly to the interior of said sleeve; a cons duit leading from and communicably connected with each regenerator; a conduit'leading from each of said distilling devices and communicably connecting the conduit from one'regenerator withthe annularflue space at one side of the partition therein; another conduit leading from each of-said distilling devices and communicably connecting 'the conduit from the other regenerator with the annular flue space at the other side of the partition therein; a shaft communicably connected with each regenerator; a gas burner in each shaft disposed in the path of flow of the heating medium to and from the regenerator; a connection for each of said regenerators and respectively adapted for connecting said regenerators with adraft means, means for controlling the air supply to each y of said regenerators; and means for controlling the connections for connecting said regenerators with a draft means; whereby the mere operation of the two last mentioned means effects the simultaneous reversal in flow of the heating medium through the regenerators and all said retorts.

2. In the heating of a plurality of low temperature distilling devices with sensible heat of gas burned outside said devices, each having a. distilling chamber for distillation of bituminous material and fluing of high tar; rom bituminous material, the method alsoby heating the air current a which'consists in flowing heat-carrier air in a current through a heat recovery plant to preheat the air and then through a gas flame burning outside of said devices, to take up flame heat and radiant heat alon with waste gas from gas flame; heating sait l devices and material being treated therein by passing the preheated and flame heated'heatcarrier air and waste gas from the as flame in a current into and out of sai devices by flowing the heat-carrier air current through fluing of high heat conductivity in said devices, whichseparates the material being treated and distilled vapors from the heat-carrier air current at all times; flowing the waste heat-carrier air in a current from said devices to and through another heat recovery plant to impart excess'heat thereto;

and subsequently reversing the direction oi How of the h'eatcarrier air.

- 3. In apparatus for low temperature disregenerators operable in alternation for preheating air and for storing heat and each having a shafttherein communicably connected with the regenerator chamber; a gas burner in each shaft disposed in thepath of so I flow of air to and from the regenerator cham ber; a conduit leading from one of i said regenerators and communicably connecting the shaft therein wit-h one of the conduits of each of said distilling devices; a conduit" leading from the other of said regenerators and communicably connecting the shaft therein with the other ofthe conduits of each' of said distilling devices; means for controlling the air supply to each of said regenerators; and connection means adapted for communicably connecting each of said regenerators with a draft; substantially as specified.

4. A process according to claim 2 char-;

acterized by maintaining gas flames continuously in each of the heat recovery lants and r it has flowed out of said distilling devices but before it flows out into the outflow operating heat recovery plant.

5. In low temperature distillatien of solid bituminous material for productlon of tar therefrom, the method which comprises: flowing heat-carrier air in a current through a heat recovery plant to preheat the air and then passing the preheated air through a flame to take up flame heat and radiant heat from the flame; flowin the preheated and flame heated heat-carrler air in heat exchange relation to, but out of contact with,

a charge of solid bituminous material; distilling said material by heat imparted thereto from the heat-carrier air while the heatcarrier air is in indirect heat exchange relation with said material; flowing the waste heat-carrier air in a current out of heat exchange relation with said charge and through another heat recovery plant to impart excess heat thereto; and subsequently reversing the direction of flow of heat-carrier air.

HEINRICH KOPPERS. 

